They are a perfectly fine airline having used them a few times over the years when friends insisted we do the skiing weekend with Easyjet rather than BA.

I believe - haven't done them in last 3 years - even Ryanair is getting better these days and I don't think there too much "low cost hell" stuff left around.

As you say, lounge can be a biggie. No issue for the odd short hop but if I had do a weekly trip with no lounge whatsoever at either end, I'd probably miss that (not least for being able to be productive and do calls in relatively privacy (the booths in EDI Spring to mind for that as I tend to go for a return flight that gets me home at decent time but before most people's working day has finished).

Food - as you say, I'd probably rather pay for something I want (if I wanted it) and I never have the nuts, crisps or sweets anyway.

Costs is always an interesting one - BA can be pretty aggressive in that space these days (hence / because of the "cuts"). So yes, if I could personally save £150 on every flight i took, I'd go for it but often they can be in similar price ranges (with with EZY being better on eg same day flexibility).

So yes, they are a serious competitor and are making a big deal about attracting business travellers. I'm still not going to be seen on the Stanstead or Luton "express" too regularly but that's because of my travel patterns and what I personally subjectively "value".